COMPARISON OF FREE RANGE AND GRADED-EXERCISE TESTING

Previous studies with athletes have demonstrated greater physiologic r esponses during free range (FR) compared with graded (GXT) exercise te sting. Since the sensitivity of clinical exercise testing depends upon the magnitude of physiologic responses, we sought to determine whethe r FR might provoke greater responses than GXT in nonathletic individua ls and patients. Healthy, physically active nonathletes and clinically stable CHD patients (N = 12) performed GXT on cycle ergometer (15 W 15 W.min(-1)) and FR (minimal time for 75 W task) on a cycle ergomete r. A starting power output was recommended for FR, bur the patients we re free to pedal at their own rates. During FR, (V) over dot O-2max (3 6.5 +/- 10.1 vs 34.1 +/- 9.4 mL.min(-1).kg(-1)), HRmax (156 +/- 25 vs 144 +/- 27 beats.min(-1)), double product (31.4 +/- 4.9 vs 29.1 +/- 5. 9) and (V) over dot E-max (111 +/- 26 vs 94 +/- 17 L.min(-1)) were all significantly greater than during cycle GXT. The mean peak power outp ut during GXT (180 +/- 45 W) was not significantly different than the mean power output during FR (204 +/- 45 W). During FR, successive ''0. 5 mile laps'' (similar to 12.5 kJ) were accomplished at power outputs of 217 +/- 45, 217 +/- 52, 192 +/- 60, 194 +/- 65, 199 +/- 63, and 207 +/- 63 W. No patient experienced angina or ECG changes during either FR or GXT. The patients uniformly reported that FR felt like ''hurryin g'' in the real world. Some patients had to make large reductions in t heir power output in mid ride to allow recovery from a too aggressive start, much as they would in the real world. We conclude that FR exerc ise provides a clinically useful method of exercise testing that is no t only more like real world exercise patterns but also provokes greate r physiologic responses than are achievable during conventional GXT.